The use of silicon substrates as an optical bench, preferably known as silicon waferboard technology, has gained a great deal of popularity in passive alignment of optoelectronic devices, passive elements and optical fibers. The use of silicon waferboard as an optical bench generally utilizes etched features in the silicon waferboard, for example the grooves for holding the optical fiber. The silicon waferboard is a monocrystalline material, anisotropic etching is done to create the v grooves for holding the fiber along the surface of the silicon wafer and alignment fiducials used to hold edge emitting optoelectronic devices and effect passive alignment. Further details of anisotropic etching to effect v grooves and alignment feducials can be found for examples in U.S. Pat. No. 4,210,923 to North et al. Furthermore, amorphous silicon can be used as the optical bench, with other known techniques such as reactive ion etching (RIE) to effect fiducials utilized for alignment.
The alignment of an optical fiber to an optoelectronic device in silicon waferboard is most readily effected by the coupling of the fiber to an edge emitting optoelectronic device. This is because of the geometry of the silicon waferboard. The fiber is usually held in an etched v groove on the silicon waferboard, and the alignment of the edge emitting optoelectronic device to the fiber relies on precision alignment pedestals on silicon waferboard and the precision notch on the edge emitting optoelectronic device. Thereafter, some type of sealing or covering is required for practical application. This type of technology has been exploited greatly. An emerging technology in the optical communications industry is surface emitting and detecting devices. Devices such as vertical cavity surface emitting lasers (VCSELs), surface emitting light emitting diodes as well as most PIN detectors have a photosensitive surface to receive or emit light from or to the top) or bottom surface. These devices have certain benefits, and alignment of devices such as these to optical fibers has proved relatively difficult requiring relatively complicated optical structures and paths to effect the coupling. Some success has been met in coupling surface emitting and detecting devices through a 90 degree molded optic coupler as is disclosed in U.S. Pat. Nos. 5,515,468 and 5,708,743 to DeAndrea, et al. the disclosures of which are specifically incorporated herein by reference. This technology which has demonstrated success from a manufacturing perspective makes use of polymer molded integrated light coupling devices suitable for coupling light from an optical electronic device to an optical fiber and vice versa. The polymer molded integrated light coupling device incorporates many functions in a single device. However, the active alignment process of turning the optical electronic device on to maximize coupling while aligning is still required.
Other techniques which incorporate the emerging silicon optical bench technology have also been used. These technologies, like the molded optic coupler of the DeAndrea, et al. patents require the device to be disposed on a different plane than the fiber with the light being communicated there between by a reflective surface. Examples of such techniques are found in U.S. Pat. Nos. 5,073,003 and 4,904,036 to Clark and Blonder respectively, the disclosures of which are specifically incorporated herein by reference. While such technology has its merits in allowing passive alignment to some extent, it is nonetheless required that the device be actively aligned and positioned so that light is properly reflected by the reflective surface. Furthermore, as can be appreciated, these devices which require a reflective surface to effect coupling reduce the efficiency of the device as there are intrinsic losses incurred at each optical surface through dispersive effects. Accordingly, a more efficient system would allow for an in line coupling between the optical fiber and the device.
U.S. Pat. No. 5,179,609 to Blonder, et al. discloses an example of the use of silicon waferboard to effect coupling between the device and the fiber in a co-linear fashion. The disclosure of this patent is specifically incorporated herein by reference. This reference makes use of two pieces of monocrystalline material as mounting members that have etched therein detense and complimentary locations on each of the pieces of the members. These detents receive microspheres to effect alignment of the mounting members to effect the coupling of the device to the fiber. This is a relatively complicated structure and not practical from manufacturing perspective. Another example of a technique for in-line alignment of an optical fiber to a surface emitting/receiving optoelectronic device is as disclosed in U.S. patent application Ser. No. 08/674,770 assigned to the assignee of the present application, to Boudreau, et al., the disclosure of which is specifically incorporated herein by reference. The reference Boudreau, et al., discloses an alignment frame for coupling an optical fiber to an optical electronic device with the optical electronic device readily and accurately placed and bonded to the frame by way of alignment pedestals and standoffs. This passive alignment member has certain benefits as are discussed in the application referenced above. The invention to Boudreau, et al., is a pigtailed device.
Accordingly, what is needed is a connectorized device which enables the coupling of an optical fiber to an optical electronic device which is either surface emitting or surface receiving in a passively aligned manner.